Author: Rishi Sharma

Administration Errors: RSV for Infants

On November 30, CDC alerted immunization programs that they have received reports of infants being mistakenly administered RSV vaccines intended for adults. Infants should only receive the RSV preventive antibody, nirsevimab (Beyfortus, Sanofi).

RSV vaccines (Arexvy by GSK and Abrysvo by Pfizer) are recommended only for adults and have not been evaluated for safety or effectiveness in infants or children. Practices that carry both adult RSV vaccine and pediatric RSV preventive antibody products should review their immunization administration safety procedures to ensure only the correct product is administered to recipients. This is an opportunity to re-educate and re-train staff on RSV immunization formulations and practices.

In the event that a vaccine administration involving RSV vaccine occurs, CDC encourages vaccinators to promptly report errors to the Vaccine Adverse Event Reporting System (VAERS). Also, inform parents of error so that these infants can receive the correct product and be monitored for adverse reactions. 

CDC Clinical Guidance (updated December 7, 2023)

Because there are no data on the efficacy/effectiveness of RSV vaccines in preventing RSV disease in this age group, the infant should receive nirsevimab if otherwise eligible based on maternal RSV vaccination status. There is no specific recommendation for a minimum interval between administration of incorrect RSV vaccine and nirsevimab. Some experts suggest:

• That it could be reasonable to consider waiting 48 to 72 hours before proceeding with nirsevimab administration. This time frame is when we would expect side effects to the RSV vaccine, such as fussiness, would be most likely.

• Consideration should be given to administering nirsevimab in the limb opposite to where the RSV vaccine was administered to avoid potential interaction or binding of RSV antibody and vaccine, thereby reducing the effectiveness of nirsevimab.

If further clinical guidance is needed, connect with our medical experts at vaccines@phila.gov or CDC experts at NIPINFO@cdc.gov.

Nirsevimab (Beyfortus) Updates

Due to the unprecedented demand for nirsevimab, supply of this product is extremely limited through both the Vaccines for Children (VFC) program and the private market. Below is an update on available supply and tips on how to prioritize use of available doses. This a rapidly evolving situation. The information in this advisory reflects the most up-to-date information available to our program at this time. Updates released after this advisory will supersede this communication.

VFC Supply 

The CDC has set up an allocation system to distribute the supply of VFC doses still available from their distribution centers. At this time, no 100 mg doses have been allocated to Philadelphia. A limited number of 50 mg doses will be available later in November and December.  

The current VFC supply shipped and allotted to Philadelphia will not cover all eligible infants. Infants face the highest risk of RSV-related hospitalization in the first 5 months of life, especially in the first month.

To facilitate more equitable access to these products for eligible infants when they are most at risk, our program will implementing the following:

• Redistribution of shipped doses. Given the supply of these products, our program will be redistributing doses that were shipped to sites last month in line with the current CDC recommendations. We will be reaching out to specific sites during the week of November 13, 2023 to coordinate picking up and delivering doses. We are basing the amounts moved on sites’ reported VFC-eligible population younger than 1 year of age, the amount of product received, and the subsequent usage.
• Prioritization of birthing hospitals. To protect eligible infants when they are at highest risk for hospitalization, we will be prioritizing distribution of the 50 mg doses to birthing hospitals.

Private Supply

Per this press release from 11/6/23, Sanofi is contacting providers about distribution plans for doses available through the private market. New orders for the 100 mg dose are no longer being accepted, as the demand exceeded the available supply for the season. Distribution of the 50 mg doses in the private market is being managed to fulfill existing orders and provide equitable access to remaining doses. Please reach out to your Sanofi representative for more information.

Protecting infants from RSV this season

Given the limited availability of nirsevimab this season, consider these measures to protect infants:

• Schedule outpatient appointments for unimmunized infants 0-2 months born during RSV season before they are > 5kg and no longer eligible for the 50 mg dose
• Utilize Synagis for qualifying infants
• Vaccinate eligible pregnant people with Abrysvo

Additional strategies are outlined in this CDC health advisory from 10/23/23.

Our program understands that this has been a challenging roll out. The Philadelphia VFC program was not aware of supply issues when fulfilling initial provider orders. We appreciate your understanding as our program works to more equitably distribute doses throughout the city as we navigate the national supply limitations. Sanofi and the CDC are working to address the issues that affected distribution this season to better prepare for the 2024 – 2025 season.